Mr. Robert I. Ponder Profile

Robert I. Ponder

Graduate Research Assistant at Tennessee Technological Univ

SPIE Involvement:

Author

Publications (4)

Proceedings Article | 1 April 2019 Presentation + Paper

Investigation of mechanical boundary conditions on impedance based structural health monitoring in a biomedical environment

Nathan Ghattas, Robert Ponder, Steven Anton

Proceedings Volume 10972, 1097228 (2019) https://doi.org/10.1117/12.2515801

KEYWORDS: Ferroelectric materials, Electromagnetic coupling, Bone, Cements, Biomedical optics, Structural health monitoring, Metals, Transducers, Surgery, In vivo imaging

Read Abstract +

Total Knee Arthroplasty is an extremely common procedure carried out across the United States. However, despite the extensive research and testing leading to new methods of surgery and improved implant designs, approximately 20% of patients are dissatisfied with their knee replacements. Like any system, there are multiple factors that can lead to failure. These include wear and loosening, which can be caused by a misalignment during surgery or unbalanced ligaments. In order to detect loosening, there have been several attempts to utilize passive sensors, such as piezoelectric transducers and strain gauges, installed in artificial knee replacements to detect a shift in the proper alignment of the implant. There has also been recent work reported that utilized the active electromechanical impedance (EMI) sensing method, which uses a single PZT in order to detect a change in the state of the monitored system, to monitor knee replacements. However, the study isolated the system so that there was no external force applied to the PZTs while the testing was performed. This work is intended to evaluate the reliability of the EMI method for monitoring of total knee replacements under an applied force in order to determine whether or not this method can be utilized in-vivo to evaluate if a replacement has failed before it becomes hazardous to the patient. This work utilizes a rectangular block of artificial bone, a rectangular block of a similar metallic alloy used in tibial trays, and a polyethylene block made of material similar to the polymer used in bearings in order to simulate the tibia, tibial tray, and bearing, respectively. The artificial bone and metallic alloy components are bonded together with bone cement, and a PZT transducer is bonded to the alloy component using superglue. The polymer component is placed on top of the PZT transducer. The system is tested under static load to monitor several stages of artificial damage. This work is intended to serve as a foundation for further in-vivo and intra-operative studies.

Proceedings Article | 1 April 2019 Presentation + Paper

Evaluation of electromechanical impedance based structural health monitoring for detection of loosening in total knee arthroplasty

Robert Ponder, R. Michael Meneghini, Steven Anton

Proceedings Volume 10972, 1097226 (2019) https://doi.org/10.1117/12.2514053

KEYWORDS: Structural health monitoring, Cements, Transducers, Algorithm development, Failure analysis, Statistical analysis

Read Abstract +

Proceedings Article | 27 March 2019 Presentation + Paper

Feasibility of force detection in 3D printed flexible material using embedded sensors

Robert Ponder, Heather Roberts, Mohsen Safaei, Steven Anton

Proceedings Volume 10970, 109702F (2019) https://doi.org/10.1117/12.2514051

KEYWORDS: Sensors, Piezoresistive sensors, Resistance, Resistors, Calibration, Computer aided design, Gait analysis, 3D modeling, Data modeling, Data acquisition

Read Abstract +

Proceedings Article | 15 March 2018 Paper

Detection of compartmental forces and location of contact areas with piezoelectric transducers in total knee arthroplasty

Mohsen Safaei, Robert Ponder, Steven Anton

Proceedings Volume 10595, 105951Q (2018) https://doi.org/10.1117/12.2296250

KEYWORDS: Transducers, Sensors, Ferroelectric materials, Surgery, Prototyping, Signal generators, In vivo imaging, Signal processing, MATLAB, Data acquisition

Read Abstract +

Total knee arthroplasty, as one of the most common surgeries in the United States, has been widely used to help restore the functionality of damaged knee joints. Alignment of the knee joint during surgery is an extremely important factor to achieve a successful operation. Several methods have been used to quantify the alignment and to provide surgeons with a repeatable method of surgery. However, lack of in vivo information has hindered establishment of correlation between intra- and postoperative knee conditions. In this work, the application of multiple piezoelectric transducers encapsulated inside the ultra high molecular weight polyethylene knee bearing for collecting in vivo data is suggested. The piezoelectric elements display the ability to sense and harvest energy from the joint during daily activity. As a sensor, piezoelectric transducers are designed to measure the compartmental forces as well as the location of the contact points between the femoral and tibial components of the knee implant. Initially, finite element analysis is performed to investigate the sensing performance of the system. In addition, a prototype instrumented bearing is fabricated and the performance of the system in measuring the forces and locations is investigated experimentally. In the experiments, the voltage signals generated by the piezoelectrics are obtained and processed to measure two components of force as well as two different contact points, one each on the medial and lateral compartments of the knee bearing. On the other hand, the actual force profile and the location of contact areas are recorded using the load frame’s built in load cell, and pressure-sensitive films, respectively, and compared to the measured data from the piezoelectrics. The result of FE simulation showed a maximum error of about 1.5% in force sensing and a maximum deviation of about 0.5 mm in the measured location of the contact points. The experimental results also showed that the measured force and location by the piezoelectric sensors match the actual quantities measured from load frame and pressure film fairly well.

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years